First part of the pre-download's available, a brief rundown:
Goronzoran, Dragon Ex souls.
Something that summons 10 BirdBirdcrows.
Planet 6 area 2 is named "Seabed". Area 9 (boss arena) is named "MarineBoss".
New enemy listings: MarineOarfish (common and rare variants; new De Rol Le?), BirdDoubleHead, BirdCentaur, Mesetan, Byakko(?--at the end of the list, no enemy file yet).
Area 2000 (formerly "DifficultQuest") is now named "Tower". It appears to be a many-floor thing where each floor has a gimmick; both Falz Arm and Dark Falz Elder can appear in it.
Lillipa3 still has no other name. It apparently has an emergency trial where you defend Lillipan homes.
Various interesting-sounding skill names (ElderSlayer, PotentialBlowFighter, HalflineAbnormal, AirStrike, CrazyBeat, RareKilling, NotoriousKilling, BoostKilling).
New Advance Quests: Ruins (uses b capsules) and Urban (uses a capsules).
New Emergency Quest (placeholder title): The Whim of the WInd (【工事中】 風のきまぐれ(仮)); yes, it's both "under construction" and a "temporary name" (condition says to kill a Rockbear, but I doubt that's for real).
New TA quest: Breakthrough Training: Dragon Altar (突破演習:龍祭壇).
New ??? quest: National Preliminaries (全国大会予選). Apparently a practice round of some sort, gives no items or exp. States that full rules will be on the official site, so it's gotta be related to that ranking thing.
A few new COs, nothing too remarkable (the standard set for a new area).
New small icons are here.
Large icons here.
(I want that samurai mag.)
EDIT: They also raised the required exp for 55-56 and 60-61 by like 30k each. Shocking.